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Abstract Background/aims The natural history of pancreatic branch duct-type intraductal papillary mucinous neoplasms (BD-IPMNs) is still unknown. This retrospective study aims to determine the morphological changes of BD-IPMNs with attention to the history of surgical resection for extrapancreatic malignancies. Methods and materials This study included 427 subjects with BD-IPMN at the Osaka Medical College from January 2001 to December 2019; 134 patients were included. The predictive factors for the progression of BD-IPMN based on morphological changes were evaluated by univariate as well as multivariate analyses. Furthermore, the clinical features of BD-IPMNs with progressive lesions during follow-up were investigated. Results The average interval of follow-up was 35.8 months (with a range between 12.1 and 157 months). Disease progression occurred in 6 subjects (4.5%). In two of them (1.5%), IPMN-related invasive carcinoma was found. Multivariate analysis demonstrated that surgical resection for extrapancreatic malignancies was a significant predictor of BD-IPMN progression. Conclusion The history of resection of extrapancreatic malignancies should be considered during the follow-up of BD-IPMN.

It is generally known that the temperature and mixture concentration in the combustion chamber influence knock intensity. It is assumed that the distribution of temperature and mixture concentration in the end-gas region of a two-stroke engine differs depending on the ignition position. Therefore, this study investigated the effect of the ignition position on knock behavior in a spark-ignition engine. A two-stroke air-cooled single-cylinder gasoline test engine was used to investigate autoignition and abnormal combustion behavior based on in-cylinder pressure analysis, in-cylinder visualization of combustion and frequency analysis of in-cylinder pressure waveforms. Six ignition positions were defined, considering the distribution of temperature and gas concentration in the cylinder. The results revealed that the ignition position influenced localized autoignition development behavior and knock intensity owing to the related distribution of temperature and fuel concentration. It was observed that knock was relatively weak when a large quantity of high-temperature residual burned gas was present in the end-gas region because it suppressed a sharp pressure rise. Knock was also relatively weak in the presence of a large quantity of fresh charge in the end-gas region because the flame was able to propagate sufficiently. Strong knock occurred when the fresh charge and residual gas were both present in the end gas-region because the high-temperature residual gas easily autoignited and autoignition developed rapidly in the new charge that readily burned. Accordingly, it was found that conditions tending to induce strong knock were present when a distribution of high-temperature areas conducive to autoignition and a distribution of high fuel concentration conducive to combustion occurred in the end-gas region. In addition, the dominant knock vibration mode was the 1,0 mode regardless of the ignition position, although it was observed that the resonant frequency varied depending on the end-gas distribution.

The purpose of this study was to develop a reactive agility test with soccer goalkeeper (GK)-specific movements (G-RAT) and to examine the reliability and validity of college-aged GKs. We designed a five-branch star-shaped course with diving and ball-catching movements under reactive conditions. In the setup, a start–goal line was set on the top of a branch and 3.5 m away from the center of the star-shaped setting. Content validity was assessed by six experts, and the item-content validity index (I-CVI) was calculated. Thirty-three male GKs performed the test trial twice. One test trial of G-RAT consists of three shuttles from the start–goal line to diving and ball-catching. For the reactive condition, GKs were instructed on which ball directions should dive when their body trunk reached 1.5 m away from the start–goal line. GKs were classified into regular (R) or non-regular (NR) groups. The intraclass correlation coefficient (ICC) and the receiver operating characteristic (ROC) curve analyses were used to assess the reliability and predictive power as convergent validity. The I-CVI was 0.83, which was greater than the acceptable level of 0.78. The ICC value was 0.94 (p < 0.01; 95% confidence interval (95%CI), 0.88–0.97). The GKs completed the test 14.3 ± 0.7 and 15.3 ± 1.0 s in the R and NR group (p < 0.01; Cohen’s d = 0.89), respectively. The area under the curves of G-RAT was 0.80 (95%CI, 0.64–0.96). These results show that a GK-specific agility test under reactive conditions would have sufficient reliability and both content and convergent validity in college-aged GKs.